I have demonstrated the distribution of neuropeptide Y (NPY) mRNA in the brain. NPY mRNA containing cell bodies are found primarily in the arcuate nucleus of the hypothalamus but can also be found scattered in the cortex, caudate-Putamen and nucleus accumbens. The distribution of NPY mRNA containing neurons correlates well with the distribution of immunohistochemically detected NPY. These results indicate that the arcuate nucleus of the hypothalamus is a key region for the central actions of NPY.